R T T F E R A 



93 



Order II.--Bdelloida. 



and . civrp like a leech ; 

 ' 



foot retractile 



Forms which swim 

 jiintrd, Iclfsrupir, termination I'mvati 



Fam. 3. PHILODINADJE. Philodina, Rotifer, C<tllii/iiin. 



Order III. Ploi'ma. 



Forms which swim only. 



Grade A. ILLOKICATA. 



Fnm. 4. HYDATINAD.E. ffi/fln/inn, filiinojis. 

 Fain. 5. SYNCHATADA Synf/i.r/ii, I'li/ifurtlira. 

 Fan). 6. NOTOMMATAD-B. Xolom main , l>i'//rnti, Fu fcnlti fi,l t 



Scaritliam, Pleurotrocha, Distcmma. 

 Fam. 7. TRIARTHHAD.E. Triartkra. 

 Fam. 8. ASPLANCHNAD^E. Asplanclm 



Grade B. LORIQATA. 

 Fam. 9. BRACIIIONID^:. Bntdiionus, Nolens, Anurxa, Sac- 



culiis. ' 



l''ain. 10. PrERODlNADte. Ptcrodiim, PompJiolyx. 

 Fam. 11. EUCHLANID.K. Eueh.lanis, Salpina, Diplax, Mono- 



s/!/lit, Colurus, Monura, Mclopodia, Stcphanops, Monoccrca, 



MasMgocerca, Dinocharis. 



Oriler IV. Scirtopoda. 



Forms which swim with their ciliary wreath, and skip by means 

 of hollow limbs with internal locomotor muscles. 



Fam. 12. PEDALIONIDJH. Pcdalion. 



The above list includes only the principal genera. There are, 

 however, a number of forms which could not be placed in any of 

 the above families. 



ABERRANT FORMS, 



Trochosphxra xquatorialis (fig. 6, G), found by Semper 

 in the Philippine Islands, closely resembles a monotrochal 



Fit;. G. Various aberrant fnrms. A, BfJatro cah'us (after Claparedc): a, mastjix. 

 B, Seiwn neljfttiiK (after Claus): m t mouth; rrf, position of the aperture of the 

 vas acffivns. C, Lindia torulosa: a, ciliated processes at the sidts of the head 

 representing: cephalotroch ; or, eye-spots. D, E, and F, Apsilus lentiformia 

 (after Mcr/jiik'iw). D, adult female Avith expanded proboscis: /, position of 

 the mouth ; s, lateral scnsc-ortrans. E. youn? free-swimming female. F, adult 

 male. G, 7r<iclt<i*jili:rr*t ;t_-<iniit'ii'ii<lix (after Semper): m, mouth ; </, ganglion; 

 (?, anus; b, velum; oc, eye-spot; c, muscles. 



polychsstoufl larva while possessing undoubtedly Rotiferal 

 characters. Mecznikow h;is described a remarkable form, 



A/ixi/i/.t l< nliformis (fig. G, D, E, and F), tho adult I'ennl'' 

 of which is entirely devoid of cilia but possesses a sort of 

 retractile hood ; the young female and the males are not 

 thus modified. Claparede discovered fixed to the bodies 

 of small Oligochsetes a curious non-ciliated form, Bnl'iiro 

 calvus (fig. 6, A), which has a worm-like very contractile 

 body and a well-developed mastax. As mentioned above, 

 the ciliation is reduced to a minimum in the curious worm- 

 like form Liiulia (fig. 6, c). Sfison nelalite (fig. 6, B), 

 living on the surface of Nebalix, which was described 

 originally by Grube, is the same form as the 8m-r,,/,,/,//,t 

 nAalix, which was supposed by Van Beneden and Hesse 

 to be a leech. It has been shown by Claus to be merely 

 an aberrant Rotifer. 



Of the curious aquatic forms Idkydium, Cheetnun/n.-i, 

 Twbanella, Dasyditis, Gepkalidium, Ckxtura, and Ilemi- 

 dasys, which Mecznikow and Claparede included under 

 the name Gastrotricha, no further account can be given 

 here. They are possibly allied to the Rotifera, but are 

 devoid of mastax and trochal disk. 



Bibliography. 



The following are some of the more important memoirs, &c. , on 

 the Rotifera. 



(1) Leeuwenhoek, Phil. Trans., 1701-1704. 



(2) EhTeii\)erg,DicI>ifiiswiist!iicjrhciialsvollkoimencOrgfinismcn, 



1838. 



(3) M. F. Dujardin, Hist. Nat. dcs Zoophytes: Infusoircs, 1841. 



(4) W. C. Williamson, "On Mcliccrta ringens," Quart. Join: 



Mict. Sci., 1853. 



(5) Ph. H. Gosse, "On Mcliccrta ringens," Quart. Jum: 



Sci., 1853. 



(6) T. H.Huxley, "QnLacinularia sodalis," Truns. M 



1853. 



(7) Fr. Leydig, " Ueber den Ban und die systematisclie Stellung 



der Raderthiere," Zcit. f. w. Zool., vi., 1854. 



(8) Ph. H. Gosse, Phil. Trans., 1856. 



(9) F. Cohn, Zcit.f, w. Zool, vii., ix., and xii. 



(10) Ph. H. Gosse, Phil. Trans., 1S58. 



(11) Pritchard, Infusoria, 1861. 



(12, 13, 14) C. T. Hudson, "On Pcdalion," Quart. Jour. Mi,-,-. 

 Sci., 1872, and Monthly Micr. Jour., 1871 and 1872. 



(15) E. Ray Lankester, "On Pcdalion," Quart. Jour. Sci., 1872. 



(16) El. Mecznikow, "On Apsilus Icntiformis," Zeit. f. w. Zool., 



1872. 



(17) C. Semper, "On Trochosnhxm" Zeit. f. w. Zool., xxii.. 



1872. 



(18) K. Eckstein, "Die Rotatorieu der Umgegend von Giessen," 



Zcit.f. w. Zool., 1883. 



(19) C. T. Hudson, "On an Attempt to reclassify Rotifers," 



Quart. Jour. Micr. Sci., 1884. 



(A. G. B.) 



Mia: 

 i: Soc., 



